By Scott Malone and Richard Valdmanis

BOSTON (Reuters) - Ethiopian runner Lelisa Desisa finished first in the Boston Marathon on Monday, reclaiming the top spot in a race he last won two years ago when it was struck by a deadly bombing attack.

Caroline Rotich of Kenya led the women's field, affirming African athletes' dominance at the race.

Desisa, who famously gave his winner's medal to the city following the 2013 bombing, pulled ahead to sprint down Boylston Street alone, finishing with a time of 2 hours, 9 minutes and 17 seconds.

"Strong Boston!" Desisa shouted after he crossed the finish line, in a version of the "Boston Strong" motto that became the city's rallying cry after the April 15, 2013, attack that killed three and injured 264.

He has no plans to donate this year's medal.

"This medal is, I think it is for me," Desisa told reporters.

Kenya's Rotich had a more dramatic finish, besting Ethiopia's Mare DiBaba in a sprint down Boylston Street, turning in a time of 2 hours, 24 minutes and 55 seconds.

Security was high near the start line in Hopkinton, along the 26.2 mile (42.16 km) course and around the finish line in Boston, in recognition of the bombing, one of the most visible attacks on U.S. soil since Sept. 11, 2001.

Desisa unseated reigning champion Meb Keflezighi of California, whose 2014 victory marked the first time that a U.S. man had won the race in three decades.

Keflezighi, who finished eighth, crossed the line hand-in-hand with another U.S. runner, Hilary Dionne, who finished 15th in the women's field.

"I've never met her. I had to sprint hard to catch up with her to do that," Keflezighi said afterward. "It was fun to do that."

The top U.S. male finisher was Dathan Ritzenhein, of Michigan, who finished seventh.

The elite men's and women's fields kept large packs for the first half of the race, with runners mindful of the early breakaway that set the stage for Keflezighi's 2014 victory.

Desisa, 25, ran shorter events before switching his focus to marathons in 2013, when he surprised the field at Boston with his fast performance. He started the race in 2014 but walked off the course with an injury.

Rotich, 30, was born in Kenya but attended high school in Japan. She has posted top-ten performances at top marathons in Tokyo, New York and Chicago.

The top U.S. women's finisher, Desiree Linden, led the pack for much of the race before Rotich passed her in the final miles, leaving Linden to finish fourth. Linden said the long lead was a strategic move intended to winnow the field.

"I know a lot of people will question it, 'Why did you run in the front and put yourself in the wind?'" Linden told reporters. "But I think that's how you have to run here. You have to be gritty and aggressive."

CONTROVERSY ON BOMBER'S TRIAL

The race comes during a pause in the trial of Dzohkhar Tsarnaev, convicted this month of killing three and injuring 264 in the 2013 bombing.

Prosecutors and defense attorneys on Tuesday are due to begin presenting another series of witnesses before the jury decides whether Tsarnaev will be sentenced to death or to life in prison without possibility of parole.

The idea of putting Tsarnaev, a 21-year-old ethnic Chechen, to death remains controversial in Boston, where polls show a deeply divided public.

Four victims of the bombing, including the families of two of the people killed by the bombs and a couple who lost legs in the blast, have now made public statements opposing seeking death for Tsarnaev.

"If there is anyone who deserves the ultimate punishment, it is the defendant. However, we must overcome the impulse for vengeance," said Jessica Kensky and Patrick Downes, who both lost legs in the attack, in a statement. "We believe that the best way to move forward and achieve our goals is a life sentence in prison without the opportunity for parole."

Last week, the parents of 8-year-old Martin Richard, the youngest to die in the attack, made a similar statement.

In both cases, the argument was not one of philosophical opposition to capital punishment but a practical one, that a sentence of life in prison without possibility of parole could spare the families and public further weeks of emotionally charged testimony and possibly years of appeals.

(Additional reporting by Svea Herbst-Bayliss; Editing by Andrew Hay and Meredith Mazzilli)